1. Field of the Invention
This invention relates to a new roofing system for protecting flat roofs or slightly sloped roofs, a method of application of said new roofing system and a method for reroofing using said new roofing system.
2. General Background
For many years coal tar pitch roofs were used. Prior to and in the 1960s and 1970s, flat roofs, with little or no slope, were very popular. One major problem with flat gravel and tar roofs is collection of water upon the roofs. Flat roofs have ineffective drainage characteristics and thus leakage problems. Thus, flat roofs have lost popularity in the past years.
Currently used roofing systems have a wide variety of shapes and forms. Reroofing may be costly to an owner and risky to a roofing contractor if not performed properly and if performed with unsuitable systems, resulting in millions of dollars of liability to the roofing contractor. Recently, modified pitched roofs comprising slopes to ensure positive drainage have been gaining popularity over previous roofs with little slope or with no slope. The present invention relates to a new roofing system for protecting flat roofs or slightly sloped roofs, a method of application of said new roofing system and a method for reroofing using said new roofing system. Said new roofing system uses a modified pitch which helps in avoiding ponding and thus increasing roof life. Also, the new roofing system can provide greater insulation characteristics. Construction and format of the new roofing system lowers utility consumption by decreasing temperature changes.
Metal sheets, used as an upper surface in the new roofing system which is put over a lower surface including but not limited to a tar and gravel covered lower surface, are essential to the new roofing system. Said metal sheets have a perimeter comprising a number of inner borders and a number of outer borders. Said new roofing system most preferably comprises, in addition to said metal sheets, a horizontal roof support placed longitudinally on the lower surface of the new roofing system, a horizontal roof deck, a central section and fasteners. A number of outer edges, comprising a number of longitudinal outer edges and a number of latitudinal outer edges, surround the lower surface of the new roofing system. The fasteners are utilized for fastening the horizontal roof support to the horizontal roof deck, and thus to underlying ceiling joists. The metal sheets are fastened to the horizontal roof support laid down between each of the number of longitudinal outer edges of the lower surface of the new roofing system and the central section of the new roofing system. A number of ridge caps is then used to connect to one another "opposite pairs of metal sheets" (i.e. metal sheets running from opposite pairs of the number of longitudinal outer edges of the lower surface of the new roofing system to the central section of the new roofing system) by covering the number of inner borders of each metal sheet located along the central section of the new roofing system, thus connecting one of the number of inner borders of each metal sheet to one of the number of inner borders of the opposite metal sheet.
The horizontal roof support comprises sets of wooden rafters or sets of metallic beams (said sets of wooden rafters or said sets of metallic beams generally referred to as "sets of beams"), with each set of beams located at a specified distance from the adjacent set of beams. Each set of beams contains an increased amount of material, whether treated wood or metal is being used, than the previous set of beams as one proceeds towards each of the number of ridge caps from each of the number of longitudinal outer edges of the lower surface of the new roofing system. On the other hand, each set of beams contains a decreased amount of material, such as treated wood or metal, than the previous set of beams as one proceeds away from each of the number of ridge caps towards each of the number of longitudinal outer edges of the new roofing system. As one proceeds parallel to the central section and towards each of the number of latitudinal outer edges of the new roofing system, the sets of beams are equivalent in height. In addition, sheet rocks comprising plaster boards are placed vertically between metal sheets and between adjacent sets of beams, thus separating metal sheets from adjacent sets of beams. The sheet rocks, along with the sets of beams, separate metal sheets from the horizontal roof deck. In addition, as an option, insulation sheets may be used to separate the metal sheets from the horizontal roof deck. Generally, insulation sheets are usually used mostly over metal buildings, but metal buildings have no existing horizontal support in advance.
A number of two-way vents may be located under each of the number of ridge caps, said number of two-way vents permitting a flow of air under the metal sheets and under the number of ridge caps.
In a most preferred embodiment, a number of channels is positioned along the number of outer borders of the metal sheets. Said number of channels is referred to as a "metal gutter" when said number of channels is not entrapped between two roofs and is solely adjacent to the metal roof. Said metal gutter would thus be fastened to the metal roof by a sealant to prevent any entrance of extraneous matter under the metal sheets through the number of outer edges of the new roofing system. A channel may exist along the sides of a sloped roof or slightly sloped roof where said channel connects the sloped roof or the slightly sloped roof to the new roofing system. Said channel, referred to as a "trough", has a roof on two opposite sides and produces a more efficient drainage system for roofing systems with a number of parapets (i.e. a low wall to protect edge of a roof).
A method of application of a new roofing system to a building comprises:
(a) removing and relocating debris, including but not limited to leaves and loose roof gravel, from top of a building; PA1 (b) using a horizontal roof deck upon ceiling joists such that said horizontal roof deck serves as a lower surface of said new roofing system; PA1 (c) fastening a horizontal roof support to said horizontal roof deck, and thus to said underlying ceiling joists, using fasteners; PA1 (d) fastening metal sheets to the horizontal roof support using fasteners, said metal sheets inclining upwards from a number of longitudinal outer edges of the lower surface towards a central section of the new roofing system forming a left upper surface and a right upper surface, with a gap existing at the central section between the left upper surface and the right upper surface of the new roofing system; PA1 (e) using a number of ridge caps to cover said gap at the central section which is located between the left upper surface and the right upper surface after having placed a number of two-way vents for transmission of air and moisture on the lower surface and at the central section of said new roofing system; PA1 (f) setting air conditioning compressors above metal sheets after supplying additional support under said air conditioning compressors and above said metal sheets; PA1 (g) sealing existing functional vents, and additional vents that are needed, to the metal sheets at the left upper surface and at the right upper surface of the new roofing system; and PA1 (h) attaching prefinished compatible metal gutters to a number of outer edges of the new roofing system such that said metal gutters surround the metal sheets and, thus, the building above which said metal sheets are installed, utilizing a number of down spouts when appropriate and supplying a number of new down spouts when needed and connecting said number of down spouts to the metal gutters.
A method for reroofing using said new roofing system comprises the steps described above for the method of application of the new roofing system. The major difference between the method for reroofing using the new roofing system and the method of application of the new roofing system is noticeable from the entitlement of the methods. For reroofing, before construction of the new roofing system begins, an original flat or slightly sloped roof exists upon which the new roofing system will be built, thus making construction of a horizontal roof deck redundant. The original roof serves as the horizontal roof deck of the new roofing system. In addition, for reroofing, existing skylights, existing gutters and nonfunctioning vents from the original roof should be removed before the construction of the new roofing system is started.
3. Description of the Prior Art
For many years, built-up roofing systems, utilizing typically a deck of wood, have been used commonly. In the built-up roofing systems, which are constructed in place, the entire roof deck is covered by a continuous weather-proof membrane such as alternate layers of felt and asphalt. Gravel, rock or similar aggregate is then spread upon the applied membrane to create a resistance to wear resulting from weather changes and foot traffic or to add weight to resist wind uplift. As an option, thermal insulation has also been applied at the inner side of the decking to minimize heat transfer through the deck. Built-up roofing systems, however, present substantial problems of expansion and contraction where extreme temperature ranges of heat and cold are encountered.
Due to the problems created by built-up roofing systems, comprising problems of expansion and contraction, prefabricated roofing systems have been developed in the past several years. Substantial on-site construction is not required for prefabricated roofing systems. Said prefabricated roofing systems, however, have several disadvantages. Often, adequate sealing provisions are not provided for obstructions such as roof-mounted equipment and parapets. Thus, due to thermal movements of the roofing system, leakage can occur. Sometimes, complicated and expensive systems using sealing membranes are required over expanse of the roofing system due to difficulty in achieving water-tight integrity of the roofing system.
In the past few years, there have been some improvements in roofing systems and in construction of the roofing systems. Numerous patents have been issued in regards to new roofing systems. Said patents disclose different innovations comprising new roofing systems, new methods of constructing said roofing systems and new methods of reroofing using said roofing systems.
Thomson et al., U.S. Pat. No. 5,222,337, discloses an insulation of flat roofs and a simultaneous construction of a gradient for positive drainage of the roofing placed on the insulation constituting a roofing layer, said roofing layer comprising rectangular elements arranged in rows parallel with the outer edges of the roof and each rectangular element having a greater thickness at two corners thereof than at opposite corners thereof.
Emblin, U.S. Pat. No. 4,864,781, discloses a multiple panel metal roofing system with overlapping panel edges, with the roofing system being installed on a continuous roof deck. Aligned support members form a support frame structure as a plurality of grid sections. Edges of planar outer skin sections overlap above the upper surface of the support members.
Perry, U.S. Pat. No. 4,831,794, discloses a system for forming a sloped surface on a pre-existing flat roof deck by using a mold assembly comprising angularly configured beams interconnected with baffle plates, such mold assembly to be filled with a light-weight cementitious or other operable material suitable for roofing.
Kelly, U.S. Pat. No. 4,642,950, discloses an arrangement and system provided for creating a sloping roof out of a flat roof and providing said sloping roof with slopes which merge into plateaus.
McClure, U.S. Pat. No. 4,608,791, discloses a fully adjustable, simplified system for setting up a sloping roof on top of an existing flat roof, wherein top and bottom roof spanning members are interconnected by individually vertically adjustable stanchions which are cross-braced in two orthogonal planes.
Tor, U.S. Pat. No. 4,423,572, discloses a water-tight insulated roof construction which utilizes an interlocking panel construction comprising a plurality of interlocking metallic panels fastened to an existing roof deck, a ridge cap, and heat insulating means positioned between said panels and said roof deck.
Charbonneau et al., U.S. Pat. No. 4,128,984, discloses a method of constructing a sloped roof by securing panels to purlins, said method comprising priming the surfaces of the purlins to be contacted by the roof panels with an organic solvent solution, allowing the solvent to volatilize, applying onto the primed surfaces a double-coated foam-backed pressure-sensitive adhesive tape, peeling away the low-adhesion web, and laying the roof panels against the exposed surface of the pressure-sensitive adhesive tape.
Each of the above mentioned patents discloses various features of a number of inventions. However, the known prior art suffers certain disadvantages. The goal of the present invention is to cure said disadvantages.